This invention pertains to tide and time calculating devices, presenting an improvement on my original patent application by the development of automatic and manual means to operate all parts of this invention in cooperation with standard and electronic clock and watch movements. Furthermore, this invention was developed in the interest of safety to navigators, fishermen, yachtsmen and shore dwellers everywhere who desire to know the tide and the time it will occur. Small craft and cabin cruisers using inland waters require to know the tides so that they may safely travel without the hazards of low water when it becomes treacherous to navigate. The field of art that this invention relates to concerns an improvement to clocks and watches for areas that have one or more tides that on clocks and watches would you find this relevant information further shown in the specifications, the drawings and the claims. This invention teaches the use of tide and calendar discs that work in registration with a twelve or twenty-four hour clock face or digital electronic clock movements having the advantages of day, date, time, AM or PM indication in addition to a new tide coordinating disc, rotatably affixed to show the occurence of tides in at least one or more places valuable to those who seek information relative to tidal information in other areas they may be traveling to. The new art also includes the method of internal movement to facilitate the rotation of internal information discs that provide day, date and movement of the AM PM factor that are moved by existing watch and clock movements. The prior art includes tide information devices that incorporate complex expensive components to render this information, none of which have taken the actual clock face into consideration, as I have, in placing calendar markings in registration with a clock face, so that each approximately fifty minutes shows lunar tides for that day or for as many days, weeks or months as the calendar disc shows. Another improvement shows the use of a seasonal tide evaluation disc that would allow of tidal adjustments manually in accordance with the various tides that differ throughout the year. Inexorably, since time has been noted historically those whose lives were regulated by the movement of the tides and by the flowing of the tidal streams have associated these events with the Moon, its rising and setting, its waxing and waning. Because the tides on the Grecian shores are very small and that their periodic movements are frequently obscured by the non-periodic changes in sea level arising from weather conditions, the ancient Greek philosophers had little first hand knowledge of the tides. Greek sailors had no experience with the regular tides on the Atlantic shores of Europe due to the blockade of the Strait of Gibraltar, maintained by the Carthaginians from 500 B.C. until their final defeat by the Romans. It was when the army of Alexander the Great reached the shores of the Arabian Sea in 325 B.C. that the Greeks experienced tides of any magnitude. It was about this period that Aristotle wrote "it is even said that the many ebbings and risings of the sea always come round with the Moon and upon certain fixed times." By 1650 it was generally accepted that the tidal movements were connected with the Moon and was unexplicable until Sir Isac Newton discovered the laws of Universal Gravitation. He published his "Principia" in 1687 and, in it, he showed that all known movements of the solar system could be concluded from the one assumption, that each particle of matter in that system acts as though it attracts every other particle with a force proportional to the square of the distance between them.
The explanation of the tides is relatively important to this invention because it shows an art of handling comparative tidal information and seasonal variables that are inseparably part of the invention. The Lunar Tide is the gravitational force, which tends to draw the Earth and the Moon towards one another, they are balanced by an equal and opposite centrifugal force caused by their monthly rotation about a common center of gravity. According to Newton's law, the gravitational pull exerted by the Moon on that part of the Earths surface nearest to the Moon must be greater than the average exerted on the whole Earth. Naturally, the diametrically opposite part would be less and these differences in attraction are termed lunar tide generating forces. The centrifugal force, however, is the same on all particles of the Earth. Therefore, the difference in attraction is directed towards the Moon at that point on the Earth's surface nearest the Moon and away at the diametrically opposite point. Only the water on the Earth's surface is free to move and consequently tends to be drawn away from the vicinity of those meridians directly under and 180.degree. from the Moon. The magnitude and time of lag of the response of the water to tide generating forces varies according to terrestrial conditions, such as the depth, shape and size of the sea in which the tidal area is located.
The Solar Tides are tide-generating forces that also arise from the differences in attraction of the Sun on parts of the Earth's surface, tending to cause low water on the meridians where Sunrise and Sunset occur and high water on the meridians directly under and 180.degree. from the Sun. Owing to the great distance between the Earth and the Sun, solar tide-generating forces are less than half of those caused by the moon.
Other tides that are important to tidal analysis should also be taken in consideration, each proving the variables that make up tides. The spring Tides occur when the Sun and the Moon are in conjunction (New Moon) or in opposition (Full Moon) the two tide-generating forces are acting on the same meridians, so that the height and range of the tide will be greater than at other periods. These tides are called Springs. Neap Tides occur when the Moon and the Sun are in quadrature, the two tide-generating forces are acting at right angles to each other, producing a tide which has a higher low water than average and a range which is smaller than at other periods. These small tides are known as Neaps. Perigee Tides occur because the Moon's orbit is elliptical and so its distance from the Earth varies throughout the month. When it is nearest to the Earth the Moon is said to be in Perigee, and when furthest away from the Earth to be Apogee. The greatest attraction beween Earth and Moon occurs at Perigee and, when this coincides with the time of the new or full Moon, the resulting spring tides are greater than average springs. Another example are the Equinoctial Springs that occurs when the lunar and solar tide-generating forces are greater than average when the Moon and the Sun have low declination and vice versa. Near the equinoxes 21st of March and 23rd of September the Sun and the Moon when New and Full both have low declination. Therefore, at about these times of the year, greater than average spring tides can be expected. The greatest spring tides will occur after a New or Full Moon which is in Perigee near the Equinox. Meteorological conditions will cause differences between the predicted and the actual tides. The variations in tidal heights are caused mainly by strong or prolonged winds and by unusually high or low barometric pressures. Barometric pressure is important; a difference from the average of 34 milibars can cause a difference in height of about one foot. A low barometer will raise sea level and a high barometer will lower it. These changes however seldom exceed one foot, but when mean sea-level is raised or lowered by strong winds or by storm surges, this effect can be important. The effect of wind on sea-level and therefore on tidal heights and times-is quite variable and depends largely upon the topography of the area in question. In general it is stated that wind will raise the sea-level in the direction toward which it is blowing. A strong wind blowing straight onshore will pile up the water and cause high waters to be higher than predicted, while winds blowing off the land will have the reverse effect. The duration of mean rise and fall of tides for any port or coastal areas are calculated empirically to give average conditions over a 19-year period in published tide tables. Apart from the meteorological influences mentioned above, tides are composed of both semidiurnal and diurnal components. River estuaries and narrow tide channels also effect tidal profiles. Even though tides can be of approximately 5 hour flood and approximately 7 hour ebb duration the average interval between successive high water and low water of semi-diurnal tides is is normally 6 hours and 13 minutes and between successive high waters 12 hours and 25 minutes. It is interesting to note that even if there is an earlier or later occurrence of high water on any day the pattern will always return to the average schedule over the full lunar cycle. Therefore from the foregoing description of tidal habits one must realize that despite all the scientific information aquired since the time of the ancient Greeks all tidal information is approximate, depending upon many variables, and a good safety margin must always be applied when using tidal information.
One object of the invention is to provide time tide devices having an AM PM disc that operates automatically on a watch or clock which may have any well known type of spring or electronic means.
Another object of the invention is to provide a power means of rotating a tide disc in the form of a bezel or a disc that would move in registration with a clock or watch face of 12 or 24 hour duration showing the state of the tide in conjunction with the time, moving in increments of approximately 50 minutes each day and specifically stopping and pointing a marker upon a watch face.
Another object of the invention is to provide a power means to rotate day date, AM or PM readouts inside a watch or clock having a special gear arrangement to turn the information as needed to operate on this invention.
Another object of the invention is to provide a calendar disc having 14 days of tides showing markings every approximate 50 minutes and being interchangeable with other discs that can be placed upon a rotatable bezel having calendar dates upon it showing the tides from the first day to the last day of a month, upon a 12 hour clock or watch face, and rotated manually or automatically by power means.
Another object of the invention is to provide a comparative secondary tide disc or bezel to a watch or clock having and showing the specific time of the tides in other related areas of travel.
Another object of the invention is to provide a seasonal variable information disc that would be responsive to giving seasonal changes due to the difference in tides at different times of the year.
Another object of the invention is to provide manually operated discs with adjustable turning outside controls as shown in the drawings.
Another object of the invention is to provide the combination of time tide improvements that would operate on standard watches and clocks and also on electronic digital readout clocks wherein the placement of tide and calendar discs would transform any watch or clock into a tidal timepiece.
Another object of the invention is to provide a calendar disc having a full month of tidal information upon it showing markings approximately every 50 minutes, in days or date marking and for placement upon a 24 hour clockface presenting infinite information on tides when moved properly at the end of each calendar month, also pertaining to watches.
Still another object of the invention is to provide a time and tide device that may be used in different combinations of the art, in any other form that incorporates this invention whether placed upon standard or electronic watches, calculators and all kinds of clocks.